It is desirable to mount an oil tank of a gas turbine engine on the fan case. This puts the oil tank forward of the high-heat areas of the engine and provides some level of ambient air cooling. It is also more easily reached for service and maintenance while freeing very limited mechanical space aft of the fan case. However, geared turbofan engines are characterized by large fan diameters that have driven fan cases to an increasing use of composites over traditional aluminum and other metals and alloys. Mounting the oil tank to the fan case is more difficult with a composite because of different coefficients of expansion between the tank and the fan case and the different profiles for deflection and loading under normal, limit, and ultimate scenarios.